How Crash Dieting Harms Your Health

Sydney McAvoy
How Crash Dieting Harms Your Health

Picture this- you are scrolling through your Instagram feed, and see one of your friends post about their weight loss. Amazed (and a little jealous), you immediately want to know what their “secret” is and reach out to them. Turns out they tried the latest trendy diet plan and it actually worked this time! You go to the company website, sign up, add their nutrition products to your cart, and are about to click “buy now,” when you pause. You start thinking about all the different “magic” diets you have tried that have promised lasting results, and how every single one of them worked in the short-term, but ultimately ended up failing to provide lasting results. Will this one be different? Let's talk about if crash diets are healthy!

Why Crash Diets Fail

If you have been in this exact situation before, I can promise you that you are not alone. The diet industry is a multi-billion dollar industry, that needs people to keep coming back in order to make money. Think about it- if these diets provided lasting results, these companies would lose their clients and source of revenue.

Now, I'm not implying that every single company focused on weight loss is out to get you, or that these diets never work. For the majority, “crash” diets are just that - a quick, excruciating experience to lose weight, before gaining the weight back.

A crash diet is defined as “a weight-loss diet undertaken with the aim of achieving very rapid results.” This usually entails reducing your calorie consumption significantly to support quick weight loss. Some diets involve replacing meals with shakes, reducing portions, limiting the foods you can eat, and others entail skipping meals. In theory, crash diets make sense. However, in practice, they often end up providing quick weight loss. Then once you go back to “normal” eating habits, you may notice you always gain weight back. So why do they fail? Here’s 5 reasons why-

Crash Diets Often Don’t Involve Any Behavior Change

When trying for quick weight loss, the method of getting there is rarely rooted in changing behaviors or providing education. More likely, it's a weight loss product or diet plan that you buy to help you reach your goal, or a simple but extreme reduction in calories. The problem here is that you don’t (and shouldn’t) keep buying those products or eating fewer than 1200 calories for the rest of your life. Crash diets don’t actually help you change habits that will make an impact in the long-term, they simply provide a way of reaching your goals very quickly. But once the program or diet is complete, then what do you do?

Quick Weight Loss Is Often Result Of Water Loss

Sorry to burst your bubble, but most of the time that quick 5-pound weight loss when you start a diet isn’t true weight loss. Usually it’s due to water losses that come with calorie restriction. This is especially true if the diet is low in carbohydrates (which most crash diets are!). When you are consuming a normal amount of carbs, your body breaks carbs down to glucose and stores to use for energy later. 

Along with each gram of glycogen, your body stores 2.6-3 grams of water. When you cut calories/carbohydrates, your body must use the stored glycogen for energy production, which also results in the loss of water. This is why you often notice a quick drop in “weight” at the beginning of a diet. Later on though, you may get frustrated with a slower decline in weight loss. 

Losing Weight Quick Negatively Impacts Metabolism

Unfortunately, not many people know that weight loss can affect metabolism negatively. Our bodies (like us) like stability and they will often fight against weight loss. Researchers have looked at weight loss and subsequent weight gain of people who chronically diet and have noticed several physiological changes that often sabotage weight loss. These include less efficient energy production (AKA slower metabolism), an increase in production of the hunger hormone Ghrelin, and decreased production of Leptin (the hormone that makes you feel full).

Blood Sugar Drops May Lead To Increased Hunger

Did you know that when you feel “hangry” it is usually due to a drop in your blood sugar levels? When your blood sugar drops, this indicates to your body that you need to eat more food to create energy. This is why balanced nutrition for stable blood sugars is so important! However, when you go from your normal eating pattern to a strict diet, your blood sugar will likely drop. This will make the body think it's starving. What will then happen is a rise in that hormone Ghrelin, making you feel incredibly hungry. If you have ever felt starving on a crash diet or out of control around food, this may be why. 

Crash Diets Interfere With Your Normal Life, Making Them Unsustainable

Last but certainly not least, crash diets are simply unsustainable in most cases. Often, they affect your social outings, family meals, and require a lot of planning to stay on “plan.” For these reasons, people often don’t stick to these diets longer than a couple months. However, for long-term weight loss, scientists have agreed that the single best diet is one that you can sustain long term. Sounds simple, but is harder to practice in theory. I don’t know about you, but I don’t want to drink shakes for the rest of my life!

TLDR: It is not your fault that crash diets fail. You aren’t lazy, unmotivated, undisciplined, incapable of following a diet, or whatever else you have told yourself in the past. The problem is with the diets themselves and the way they are structured to make you fail!

How Crash Dieting Harms Your Health

Now that we have looked at why crash dieting fails, let’s take a look at how these crash diets may harm your health. 

May Cause Loss of Lean Body Mass

When you lose weight too quickly, you may lose lean body mass (muscle and bone) alongside the fat. In fact, very calorie-restricted crash diets can cause up to a 25% loss in lean body mass when you don’t take proper dietary interventions under physician or dietitian supervision. This loss of lean body mass can cause problems later on with both bone health and metabolism.

Increases Your Risk For Heart Disease and Diabetes

Yo-yo dieting is the constant diet cycle in which you crash diet, lose weight, get off the diet, gain weight back, go on another diet, and the cycle repeats. Weight fluctuations up and down while yo-yo dieting has been associated with adverse health outcomes. Researchers have found that diet-related weight fluctuations significantly increases all-cause mortality, risk of heart disease and hypertension, altered glucose metabolism, and increases the risk of diabetes. 

Disrupts Normal Bowel Habits

When you go on a very low calorie diet or restrict certain food groups, you can miss out on essential nutrients that help you go. For example, a diet low in carbohydrates may also lack essential fiber that keeps your bowel movements normal. In general, when you have less food passing through your gut on a low calorie diet, you won’t poop as much as you would if you were eating more food, which may often lead to constipation due to reduced gut motility.  

Can Lead To Nutrient Deficiencies 

When you significantly reduce the amount of food you eat or limit certain food groups, it can be hard to meet the minimum requirements for the essential vitamins and minerals we need from our food! Let’s be real, it can be hard to meet certain nutrient requirements even without being on a crash diet. Even when following a more sustainable diet, it is important to monitor your nutrient levels when making changes to your diet. Vessel’s at-home wellness test can help you monitor important nutrients, as well as your hydration and pH levels, all of which are affected by dieting. 

Often Causes Low Energy Levels

Remember when we talked about glycogen stores needed for energy production? When you crash diet and lose those stores, it can be hard for your body to produce energy as needed, which may result in low energy levels or irritability. Additionally, if you are unable to meet your vitamin and mineral requirements from your diet, energy production will become less efficient, resulting in increased fatigue

Increases Risk of Developing Gallstones

While the risk of gallstones may depend on the person, very low calorie diets and subsequent fast weight loss may increase your risk of forming them. When you lose weight quickly (the intention of any crash diet), your liver releases extra cholesterol into the bile and your gallbladder may not empty properly. Both of these factors can increase gallstone risk. Another factor that increases your risk of developing gallstones? Weight cycling that comes with yo-yo dieting.

Change Your Lifestyle, Quick Crash Dieting!

The bottom line here is that you should know the risks associated with crash dieting before you hit that “buy now” button on the next popular diet you come across. The better alternative? Find a healthy, sustainable diet that provides the nutrients you need and you can stick to long-term. But you don’t have to do this alone. We recommend reaching out to one of our Vessel nutrition coaches for help getting started on a diet that works for you! What is one long-term change to your diet you would like to make?